.premium-features {
            background: linear-gradient(135deg, #667eea 0%, #764ba2 100%);
            color: white;
            border-radius: 10px;
            padding: 2rem;
            margin: 2rem 0;
        }
        .feature-card {
            background: rgba(255,255,255,0.1);
            border-radius: 10px;
            padding: 1.5rem;
            margin: 1rem 0;
            backdrop-filter: blur(10px);
        }
        .drop-zone {
            border: 3px dashed #007bff;
            border-radius: 15px;
            padding: 3rem 2rem;
            text-align: center;
            transition: all 0.3s ease;
            background: #f8f9fa;
            cursor: pointer;
        }
        .drop-zone.dragover {
            border-color: #28a745;
            background: #e8f5e8;
        }
        .file-preview {
            max-height: 400px;
            overflow-y: auto;
        }
        .page-range-examples {
            background: #e9ecef;
            border-radius: 8px;
            padding: 1rem;
            margin: 1rem 0;
        }
        .progress-container {
            display: none;
            margin: 2rem 0;
        }
        .result-alert {
            display: none;
            margin: 1rem 0;
        }

         /* How It Works Section */
        .how-it-works {
            margin-top: 60px;
            padding: 50px 30px;
            background: white;
            border-radius: var(--border-radius);
            box-shadow: var(--shadow);
            transition: var(--transition);
        }

        .how-it-works:hover {
            transform: translateY(-5px);
            box-shadow: 0 15px 40px rgba(0, 0, 0, 0.1);
        }

        .section-header {
            text-align: center;
            margin-bottom: 40px;
            position: relative;
        }

        .section-header h2 {
            font-weight: 700;
            color: var(--dark);
            font-size: 2.2rem;
            display: inline-block;
            position: relative;
        }

        .section-header h2::after {
            content: '';
            position: absolute;
            bottom: -10px;
            left: 50%;
            transform: translateX(-50%);
            width: 80px;
            height: 4px;
            background: linear-gradient(135deg, var(--primary) 0%, var(--secondary) 100%);
            border-radius: 2px;
        }

        .steps {
            display: flex;
            justify-content: space-between;
            flex-wrap: wrap;
        }

        .step {
            flex: 1;
            min-width: 200px;
            text-align: center;
            padding: 0 15px;
            margin-bottom: 20px;
        }

        .step-number {
            display: flex;
            align-items: center;
            justify-content: center;
            width: 60px;
            height: 60px;
            background: linear-gradient(135deg, var(--primary) 0%, var(--secondary) 100%);
            color: white;
            border-radius: 50%;
            font-size: 24px;
            font-weight: bold;
            margin: 0 auto 20px;
            box-shadow: 0 5px 15px rgba(74, 108, 247, 0.3);
            transition: var(--transition);
        }

        .step:hover .step-number {
            transform: scale(1.1);
        }

        .step h3 {
            margin-bottom: 10px;
            color: var(--dark);
        }

        .step p {
            color: var(--gray);
        }